The city of Lille in France was a pioneer with its innovative sustainable public transport system back in 1997. And today, residents are still reaping the benefits as they have a way to dispose of waste, get from A to B and reduce the effects of climate change, all at once.
by Gildas Le Saux
The Lille metropolitan area has 1.1 million inhabitants. It is the fourth largest metropolitan area in France and has the peculiarity of bordering Belgium.
The Lille Métropole Communauté Urbaine (LMCU) is the public body forming the basis for community cooperation in this region. LMCU brings together 85 towns and villages, within a territory which has both urban and rural parts. The main goals when the LMCU was formed, were concerned initially with urban planning issues and public service provision, but have evolved since new legislation was brought in (in July 1999) to further extend the links between the constituent communes. The president of LMCU is former French prime minister, Pierre Mauroy.
LMCU is accountable for several urban management issues such as road development and maintenance, water supply, waste water treatment, and waste collection and treatment. (The scope of the waste and sewage management being restricted to household).
The fact that LMCU was responsible for both waste management and public transport systems led to a situation in the late 1990s, where it was deemed beneficial to start producing biomethane from waste and using it to run the public bus network. The LCMU has a mobility policy aiming to increase the use of clean transport methods, such as the metro and gas-powered buses, as well as a sustainable waste management policy which promotes the recovery of as much usable material as possible from the waste stream – in particular, biowaste.
Biomethane fuel
Biogas is a renewable resource that can be made from biowaste (including kitchen waste and green waste) and from sewage sludge coming from waste water treatment.
First, organic waste is digested in an anaerobic digestion chamber. Raw biogas is then upgraded to produce a fuel called ‘biomethane’ which is equivalent to natural gas in quality. This biomethane can either be used in natural gas vehicles (called NGVs) or injected into the natural gas grid. Natural gas as a vehicle fuel is delivered as compressed natural gas (CNG) or lique?ed natural gas (LNG). As this fuel is produced from organic material, it does not contribute to climate change.
Lille – the pioneer city
The Lille metropolitan area was the pioneer city in 1997. Its buses began to be refuelled with biomethane coming from sewage sludge recovery at the waste water treatment located in Marquette. This so-called ‘pilot’ project fuelled four gas-driven buses until 2004.
This first exploration into the possibilities of using biowaste and sewage sludge to power buses has greatly helped the development of biomethane as a vehicle fuel in Lille (and in Europe). The second driving force on the road to success, has been the Urban Mobility Plan, launched in 1999, which stated that the entire fleet of diesel buses should be gradually replaced with gas-powered buses. Today, 400 buses run on compressed gas and by 2011 the whole fleet will run on gas.
The Organic Recovery Centre
Another major factor contributing to the success of this project was the construction of the Organic Recovery Centre (ORC).
The ORC treats approximately100,000 tonnes of biowaste per year, of which 60,000 tonnes are turned into biomethane and 40,000 tonnes are used for compost production. The biowaste mainly comes from households (collected door-to-door selectively), recycling centres and public catering.
From this biowaste, the ORC produces four million cubic metres of biomethane, which is the equivalent to four millions litres of diesel (i.e. the amount consumed by 100 buses per year). This biomethane goes straight to the buses located in the bus depot which is just 100 metres from the production plant.
The ORC was the result of a 15-year technical and political process which arose from the adoption of an energy recovery policy, and therefore led to the production of biomethane. The ORC is owned by LMCU local authority but it is run by the private sector (Carbiolane society). The buses are run by Transpole company and waste collection is operated by Esterra.
The use of biomethane as a vehicle fuel in Lille is already a reality. However, some administrative authorizations are still pending regarding its use. These are needed for transporting gas to the bus depot or injecting biomethane into the natural gas grid.
In lieu of these authorizations (which are expected sometime in 2010), the ORC has – up till now – fuelled waste collection trucks and service cars on the site of the plant itself, with a temporary compression unit. In 2009, 9000 Nm3 (cubic metres per hour) of biomethane were used as a fuel for three vehicles, with no problems.
The technology
The Organic Recovery Centre is designed to treat 108,600 tonnes of biowaste per year. The feedstock is made up of:
- the biowaste fraction of household waste resulting from the selective door-stop collection = 36,000-62,000 tonnes/year,
- green waste and municipal waste collected at recycling centres = 40,600-56,700 tonnes/year,
- food waste from catering = 2700-6300 tonnes/year.
In terms of energy management, the facility’s heating needs are met by a biogas boiler. Over 85% of the facility’s water needs are met by rainwater recovery, and priority is given to on-site recycling of process water. The system for purifying biogas and turning it into fuel (upgrading process) also uses water recovered from the roof. No liquid effluents are discharged into the environment.
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Bus getting its waste-derived biofuel at a filling station. |
The air in the building must be treated and is done at a rate of 350,000 m³/hour:
- 1st stage: washing with sulphuric acid (physical chemical stage)
- 2nd stage: biofilter
There is no discharge of fossil CO2. The CO2 discharged comes from composting biomass produced by photosynthesis and from biogas upgrading.
The process: from waste to biomethane fuel, is:
- After preparation, biowaste undergoes oxygen-free treatment in digesters, each measuring 1,900 m³, for around 21 days at 57°C.
- The biodigestion phase: raw biogas is recovered in the upper part of the digesters. Raw biogas is partly used for heating the facility.
- Upgrading biogas involves purifying the raw biogas, the latter being made up of around 55% methane, and turning it into biomethane as a fuel made up of 97% methane. The technology used is water scrubbing. During this upgrading phase, the CO2, water and pollutants, such as hydrogen sulphide (H²S) which is very corrosive to engines, are removed.
- One storage unit of two horizontal tanks (with a capacity of 5000 Nm3) at 9 to 20 bars has been set up as a way to cope with the fact there is continuous biomethane production, but the consumption is not continuous (buses are mainly refuelled at night).
- Another solution exists for distributing biomethane, namely grid injection. Injecting biomethane into the natural gas grid will be a way of ensuring stable biomethane production, improving the efficiency of the system.
Biogasmax project
Since 2006, LMCU has been running the Biogasmax project, which is a European R&D project funded by the European Commission and dedicated to biomethane as a vehicle fuel.
Biogasmax has 28 partners and will run until September 2010. Many national conferences (Sweden, Germany, France) will be organized by September to disseminate the results of the demonstrations and research carried out over four years. Technical reports and training material (decision guides, videos, conferences proceedings, etc.) are available online.
Lille’s part in new legislation
As LMCU is the first local authority to produce and use biomethane fuel, its experience has greatly helped the process of implementing legislation which supports this type of renewable energy. It has been a long process, which started in 2004.
- An agreement between former Gaz de France and LMCU on gas standards for grid injection was made between 2005 and 2007. In October 2008, after a request from LMCU, the National Health Agency (AFSSET) published the health assessment: it concluded that using biomethane does not create any more danger for people than the use of natural gas.
- LMCU participated in the Grid Injection Working Group led by the French Ministry of Environment in 2009. Together with national partners, LMCU made proposals regarding feed-in tariffs system applied to biomethane.
- Authorization for grid injection is planned for year 2010. By now, the Lille site is the only area in France where grid injection of biomethane is feasible.
Gildas Le Saux is a Biogasmax project manager See biogasmax.eu
e-mail: glesaux@lillemetropole.fr
Biogasmax projects in Europe
The Biogasmax objective is to develop alternative and affordable modes of transport, as well as improving the management and use of waste.
The European Union is increasingly dependent on imported fossil fuel.This complex situation leads to significant ecological and economical risks for society. The European Commission is seeking to solve these issues through a series of initiatives, including many that focus on the transport industry, which is almost fully dependent on oil. In this context, it has launched a call for projects that focus on biofuels (Biofuel Cities).
Biogas used as fuel (biomethane) can eliminate smog in the atmosphere and significantly reduce noise pollution. The most environmentally harmful compounds (particles, non-methane hydrocarbons) are absent when biomethane is used. For example, using biomethane as a fuel in buses leads to a reduction of 95% in particles, 99% in sulphur compounds and 70% in nitrogen oxide, as compared to diesel buses.
The European Biogasmax project creates a network of biogas-related schemes in Europe with the aim of sharing experiences in terms of best practice in managing urban transportation.The objective of the Biogasmax project is to address urban challenges related to air and water pollution, as well as waste.
To this end, it uses a virtuous cycle in which biogas is produced from various types of urban waste that must be managed. During the process, Biogasmax focuses on monitoring the economic and environmental impact in order to produce fuel for transport that does not harm the environment.
The research and development projects carried out in the context of Biogasmax are closely tied to the following four main fields of technological activities:
- Production of biogas from various types of waste;
- Upgrading of biogas to a high-quality fuel;
- Distribution for transport and injection into natural gas grids;
- Use in vehicles to increase the number of biomethane-fueled vehicles.
